Acute Lung Injury and Multiple Organ Dysfunction Syndrome Secondary to Intra-Abdominal Hypertension and Abdominal Decompression in Extensively Burned Patients

Abdominal Compartment Syndrome-When Is Surgical Decompression Needed?

Compartment syndrome occurs when increased pressure inside a closed anatomical space compromises tissue perfusion. The sudden increase in pressure inside these spaces requires rapid decompression by means of surgical intervention. In the case of abdominal compartment syndrome (ACS), surgical decompression consists of a laparostomy. The aim of this review is to identify the landmarks and indications for the appropriate moment to perform decompression laparotomy in patients with ACS based on available published data. A targeted literature review was conducted on indications for decompression laparotomy in ACS. The search was focused on three conditions characterized by a high ACS prevalence, namely acute pancreatitis, ruptured abdominal aortic aneurysm and severe burns. There is still a debate around the clinical characteristics which require surgical intervention in ACS. According to the limited data published from observational studies, laparotomy is usually performed when intra-abdominal pressure reaches values ranging from 25 to 36 mmHg on average in the case of acute pancreatitis. In cases of a ruptured abdominal aortic aneurysm, there is a higher urgency to perform decompression laparotomy for ACS due to the possibility of continuous hemorrhage. The most conflicting recommendations on whether surgical treatment should be delayed in favor of other non-surgical interventions come from studies involving patients with severe burns. The results of the review must be interpreted in the context of the limited available robust data from observational studies and clinical trials.

Activation of PI3K/Akt/HIF-1α Signaling is Involved in Lung Protection of Dexmedetomidine in Patients Undergoing Video-Assisted Thoracoscopic Surgery: A Pilot Study

Background

Lung resection and one lung ventilation (OLV) during video-assisted thoracoscopic surgery (VATS) may lead to acute lung injury. Dexmedetomidine (DEX), a highly selective α₂ adrenergic receptor agonist, improves arterial oxygenation in adult patients undergoing thoracic surgery. The aim of this pilot study was to explore possible mechanism related to lung protection of DEX in patients undergoing VATS.

Patients and Methods

Seventy-four patients scheduled for VATS were enrolled in this study. Three timepoints (before anesthesia induction (T₀), 40 min after OLV (T₁), and 10 min after two-lung ventilation (T₂)) of arterial blood gas were obtained. Meanwhile, lung histopathologic examination, immunohistochemistry analysis (occludin and ZO-1), levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6 in lung tissue and plasma, and activation of phosphoinositide-3-kinase (PI3K)/AKT/hypoxia-inducible factor (HIF)-1α signaling were detected. Postoperative outcomes including duration of withdrawing the pleural drainage tube, length of hospital stay, hospitalization expenses, and postoperative pulmonary complications (PPCs) were also recorded.

Results

Sixty-seven patients were randomly divided into DEX group (group D, n=33) and control group (group N, n=34). DEX improved oxygenation at T₁ and T₂ (group D vs group N; T₁: 191.8 ± 49.8 mmHg vs 159.6 ± 48.1 mmHg, P = 0.009; T₂: 406.0 mmHg [392.2–423.7] vs 374.5 mmHg [340.2–378.2], P = 0.001). DEX alleviated the alveolar capillary epithelial structure damage, increased protein expression of ZO-1 and occludin, inhibited elevation of the expression of TNF-α and IL-6 in lung tissue and plasma, and increased protein expression of p-PI3K, p-AKT and HIF-1α. Dex administered had better postoperative outcomes with less risk of PPCs and hospitalization expenses as well as shorter duration of withdrawing the pleural drainage tube and length of hospital stay.

Conclusion

Activation of PI3K/Akt/HIF-1α signaling might be involved in lung protection of DEX in patients undergoing VATS.

Timing of surgical intervention for compartment syndrome in different body region: systematic review of the literature

Compartment syndrome can occur in many body regions and may range from homeostasis asymptomatic alterations to severe, life-threatening conditions. Surgical intervention to decompress affected organs or area of the body is often the only effective treatment, although evidences to assess the best timing of intervention are lacking. Present paper systematically reviewed the literature stratifying timings according to the compartmental syndromes which may beneficiate from immediate, early, delayed, or prophylactic surgical decompression. Timing of decompression have been stratified into four categories: (1) immediate decompression for those compartmental syndromes whose missed therapy would rapidly lead to patient death or extreme disability, (2) early decompression with the time burden of 3-12 h and in any case before clinical signs of irreversible deterioration, (3) delayed decompression identified with decompression performed after 12 h or after signs of clinical deterioration has occurred, and (4) prophylactic decompression in those situations where high incidence of compartment syndrome is expected after a specific causative event.

200mM hypertonic saline resuscitation attenuates intestinal injury and inhibits p38 signaling in rats after severe burn trauma

BACKGROUND

An overabundant discharge of inflammatory mediators plays a significant role in intestinal injury throughout the early stages of critical burns. The present study aims to explore the outcome of 200mM hypertonic saline (HS) resuscitation on the intestinal injury of critically burned rats.

MATERIALS AND METHODS

Fifty-six Sprague-Dawley rats were randomized into three groups: sham group (group A), burn plus lactated Ringer's group (group B), and burn plus 200mM HS group (group C). Samples from the intestine were isolated and assayed for wet-weight-to-dry-weight (W/D) ratio, histopathology analyses, and p38 mitogen-activated protein kinase (MAPK) activity. Serum interleukin 1β (IL-1β) and high mobility group protein box 1 (HMGB1) concentrations were also examined.

RESULTS

Initial resuscitation with 200mM Na⁺ HS significantly decreased the intestinal W/D ratio and improved intestinal histopathology caused by severe burn. HS resuscitation also inhibited the increase of serum IL-1β and HMGB1 concentrations, and p38 MAPK activity in the intestine of critically burned rats.

CONCLUSIONS

The overall findings of this study suggest that preliminary resuscitation with 200mM HS after severe thermal injury reduces intestinal edema, inhibits systemic inflammatory response, and attenuates intestinal p38 MAPK activation, thus reduces burns-induced intestinal injury.

Respiratory functions of burn patients undergoing decompressive laparotomy due to secondary abdominal compartment syndrome

INTRODUCTION

The development of secondary abdominal compartment syndrome (ACS) is associated with multiple organ dysfunction. There is little information about the effects of decompressive laparotomy (DL) on respiratory function (RF) in burn patients developing ACS.

PATIENTS AND METHODS

We retrospectively obtained data characterising RF from the database of an adult burn intensive care unit (BICU). Peak inspiratory pressure (Pip), PaO2/FiO2-ratio (P/F), static compliance (Cstat) and airway resistance (Raw) were analysed over the course of 60 h at 8 time points relative to DL.

RESULTS

Thirty-five patients with ACS underwent DL with a mean percentage of total burned body surface area (TBSA) 39 ± 23% and mean intra-abdominal pressure 33 ± 7 mmHg. All patients presented with significantly deteriorating RF within 12h of DL (Pip 33 ± 4 to 39 ± 7 cm/H2O, p=0.003; P/F 232 ± 59 to 160 ± 55 mmHg, p<0.001, Cstat 34 ± 5 to 26 ± 6 mL/cmH2O, p<0.001; Raw 18 ± 3 to 24 ± 9 cm H2O/L/s, p=0.02). All these parameters improved significantly (p<0.001) after DL, regardless of the presence of inhalation injury or torso burns. Mortality was 71.4%.

CONCLUSIONS

Variables characterising RF demonstrated a rapid deterioration before and a significant and sustained improvement after DL in burn patients developing ACS. Despite these respiratory improvements, DL was associated with low survival rates. Secondary ACS remains a challenge in burn patients and thus warrants particular attention during intensive care treatment.

Respiratory failure after pediatric scald injury

OBJECTIVE

A subset of children with scald burns develops respiratory failure despite no direct injury to the lungs. We examined these patients in an effort to elucidate the etiology of the respiratory failure.

METHODS

The charts of pediatric patients with greater than 10% total body surface area (TBSA) scald burns were reviewed. Age, weight, burn distribution, percentage of TBSA burned, resuscitation volumes, Injury Severity Score, evidence of abuse, length of stay, days in the intensive care unit, and time and duration of intubation were recorded.

RESULTS

Two hundred thirty-two patients met our inclusion criteria. Of these, 220 patients did not require intubation, and 12 of the patients did. No patient older than 3 years or with burns less than 15% TBSA required intubation. Fluid over resuscitation was not directly associated with respiratory failure requiring mechanical ventilation.

CONCLUSIONS

We report the largest published series of patients with scald burns requiring mechanical ventilation in the absence of direct airway injury. Five percent of pediatric patients required mechanical ventilation after scald injury. We believe that a combination of causes including fluid resuscitation, young patient age, small patient size, and possible activation of the systemic inflammatory immune response may be responsible for the respiratory failure.

Effect of increased intra-abdominal pressure and decompressive laparotomy on aerated lung volume distribution

Increased intra-abdominal pressure (IAP) is common in intensive care patients, affecting aerated lung volume distribution. The current study deals with the effect of increased IAP and decompressive laparotomy on aerated lung volume distribution. The serial whole-lung computed tomography scans of 16 patients with increased IAP were retrospectively analyzed between July 2006 and July 2008 and compared to controls. The IAP increased from (12.1+/-2.3) mmHg on admission to (25.2+/-3.6) mmHg (P<0.01) before decompressive laparotomy and decreased to (14.7+/-2.8) mmHg after decompressive laparotomy. Mean time from admission to decompressive laparotomy and length of intensive-care unit (ICU) stay were 26 h and 16.2 d, respectively. The percentage of normally aerated lung volume on admission was significantly lower than that of controls (P<0.01). Prior to decompressive laparotomy, the total lung volume and percentage of normally aerated lung were significantly less in patients compared to controls (P<0.01), and the absolute volume of non-aerated lung and percentage of non-aerated lung were significantly higher in patients (P<0.01). Peak inspiratory pressure, partial pressure of carbon dioxide in arterial blood, and central venous pressure were higher in patients, while the ratio of partial pressure of arterial O(2) to the fraction of inspired O(2) (PaO(2)/FIO(2)) was decreased relative to controls prior to laparotomy. An approximately 1.8 cm greater cranial displacement of the diaphragm in patients versus controls was observed before laparotomy. The sagittal diameter of the lung at the T6 level was significantly increased compared to controls on admission (P<0.01). After laparotomy, the volume and percentage of non-aerated lung decreased significantly while the percentage of normally aerated lung volume increased significantly (P<0.01). In conclusion, increased IAP decreases total lung volume while increasing non-aerated lung volume. Decompressive laparotomy is associated with resolution of these effects on lung volumes.

Intra-abdominal hypertension: detecting and managing a lethal complication of critical illness

Intra-abdominal hypertension occurs in 50% of all patients admitted to the intensive care unit and is associated with significant morbidity and mortality. Intra-abdominal hypertension is defined as a sustained, pathologic rise in intra-abdominal pressure to 12 mm Hg or more. Patients with intra-abdominal hypertension may progress to abdominal compartment syndrome. Early identification and treatment of this condition will improve patient outcome. Patients at risk for intra-abdominal hypertension include those with major traumatic injury, major surgery, sepsis, burns, pancreatitis, ileus, and massive fluid resuscitation. Predisposing factors include decreased abdominal wall compliance, increased intraluminal contents, increased peritoneal cavity contents, and capillary leak/fluid resuscitation.

Early fluid resuscitation with hyperoncotic hydroxyethyl starch 200/0.5 (10%) in severe burn injury

Introduction

Despite large experience in the management of severe burn injury, there are still controversies regarding the best type of fluid resuscitation, especially during the first 24 hours after the trauma. Therefore, our study addressed the question whether hyperoncotic hydroxyethyl starch (HES) 200/0.5 (10%) administered in combination with crystalloids within the first 24 hours after injury is as effective as 'crystalloids only' in severe burn injury patients.

Methods

30 consecutive patients were enrolled to this prospective interventional open label study and assigned either to a traditional 'crystalloids only' or to a 'HES 200/0.5 (10%)' volume resuscitation protocol. Total amount of fluid administration, complications such as pulmonary failure, abdominal compartment syndrome, sepsis, renal failure and overall mortality were assessed. Cox proportional hazard regression analysis was performed for binary outcomes and adjustment for potential confounders was done in the multivariate regression models. For continuous outcome parameters multiple linear regression analysis was used.

Results

Group differences between patients receiving crystalloids only or HES 200/0.5 (10%) were not statistically significant. However, a large effect towards increased overall mortality (adjusted hazard ratio 7.12; P = 0.16) in the HES 200/0.5 (10%) group as compared to the crystalloids only group (43.8% versus 14.3%) was present. Similarly, the incidence of renal failure was 25.0% in the HES 200/0.5 (10%) group versus 7.1% in the crystalloid only group (adjusted hazard ratio 6.16; P = 0.42).

Conclusions

This small study indicates that the application of hyperoncotic HES 200/0.5 (10%) within the first 24 hours after severe burn injury may be associated with fatal outcome and should therefore be used with caution.

Trial registration

NCT01120730.

Intra-abdominal pressure and abdominal compartment syndrome in acute general surgery

BACKGROUND

Intra-abdominal pressure (IAP) is a harbinger of intra-abdominal mischief, and its measurement is cheap, simple to perform, and reproducible. Intra-abdominal hypertension (IAH), especially grades 3 and 4 (IAP > 18 mmHg), occurs in over a third of patients and is associated with an increase in intra-abdominal sepsis, bleeding, renal failure, and death.

PATIENTS AND METHODS

Increased IAP reading may provide an objective bedside stimulus for surgeons to expedite diagnostic and therapeutic work-up of critically ill patients. One of the greatest challenges surgeons and intensivists face worldwide is lack of recognition of the known association between IAH, ACS, and intra-abdominal sepsis. This lack of awareness of IAH and its progression to ACS may delay timely intervention and contribute to excessive patient resuscitation.

CONCLUSIONS

All patients entering the intensive care unit (ICU) after emergency general surgery or massive fluid resuscitation should have an IAP measurement performed every 6 h. Each ICU should have guidelines relating to techniques of IAP measurement and an algorithm for management of IAH.

Association between blood lactate levels, Sequential Organ Failure Assessment subscores, and 28-day mortality during early and late intensive care unit stay: a retrospective observational study

OBJECTIVES

To evaluate whether the level and duration of increased blood lactate levels are associated with daily Sequential Organ Failure Assessment (SOFA) scores and organ subscores and to evaluate these associations during the early and late phases of the intensive care unit stay.

DESIGN

Retrospective observational study.

SETTING

Mixed intensive care unit of a university hospital.

PATIENTS

134 heterogeneous intensive care unit patients.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We calculated the area under the lactate curve above 2.0 mmol/L (lactateAUC>2). Daily SOFA scores were collected during the first 28 days of intensive care unit stay to calculate initial (day 1), maximal, total and mean scores. Daily lactateAUC>2 values were related to both daily SOFA scores and organ subscores using mixed-model analysis of variance. This was also done separately during the early (<2.75 days) and late (>2.75 days) phase of the intensive care unit stay.Compared with normolactatemic patients (n = 78), all median SOFA variables were higher in patients with hyperlactatemia (n = 56) (initial SOFA: 9 [interquartile range 4-12] vs. 4 [2-7]; maximal SOFA: 10 [5-13] vs. 5 [2-9]; total SOFA: 28 [10-70] vs. 9 [3-41]; mean SOFA: 7 [4-10] vs. 4 [2-6], all p < .001). The overall relationship between daily lactateAUC>2 and daily SOFA was an increase of 0.62 SOFA-points per 1 day.mmol/L of lactateAUC>2 (95% confidence interval, 0.41-0.81, p < .00001). During early intensive care unit stay, the relationship between lactateAUC>2 and SOFA was 1.01 (95% confidence interval, 0.53-1.50, p < .0005), and during late intensive care unit stay, this was reduced to 0.50 (95% confidence interval, 0.28-0.72, p < .0005). Respiratory (0.30, 0.22-0.38, p < .001) and coagulation (0.13, 0.09-0.18, p < .001) subscores were most strongly associated with lactateAUC>2.

CONCLUSIONS

Blood lactate levels were strongly related to SOFA scores. This relationship was stronger during the early phase of intensive care unit stay, which provides additional indirect support for early resuscitation to prevent organ failure. The results confirm that hyperlactatemia can be considered as a warning signal for organ failure.

The year in burns 2007

In the year 2007, approximately 1000 original burn research articles were published in scientific journals using the English language. This article reviews approximately 90 of these which were deemed by the author to be the most important in terms of clinical burn care. Relevant topics include epidemiology, wound characterisation, critical care physiology, inhalation injury, infection, metabolism and nutrition, psychological considerations, pain management, rehabilitation, and burn reconstruction. Each selected article is mentioned briefly with editorial comment.